The Supreme Court upheld President Obama’s health care law today in a splintered, complex opinion that gives Obama a major election-year victory.

Basically, a bare majority of the justices said that the individual mandate — the requirement that most Americans buy health insurance or pay a fine — is constitutional as a tax.

“Because the Constitution permits such a tax, it is not our role to forbid it, or to pass upon its wisdom or fairness,” wrote Chief Justice John Roberts wrote in an opinion that reflected a 5-4 vote on on the question.

Roberts — a conservative appointed by President George W. Bush — provided a key vote to preserve the landmark health care law, which figures to be a major issue in Obama’s re-election bid against Republican opponent Mitt Romney.